2 — Thinner, more or less greenish. 



Elliptical, base and hinge line parallel. 



Genus ANODONTOIDES 61 

 Ovate, etc., narrowing more or less posteriorly. 



Genus ANODONTA 62 

 (Toothless forms of Margaritana monodonta and 

 Lampsilis leptodon might be sought in this group. 

 The former is heavy, nearly 3 times as long as 

 wide, dark and opaque. The latter is flat, has 

 more or less distinct rays, and the valves are 

 somewhat distorted, and do not fit closely.) 



KEY TO SPECIES 



In the following key the name only is given when the genus is represented 

 by but one species in Iowa. The numbers preceding the names correspond 

 to the numbers opposite the generic names in the preceding key. 



1. — PJiilomycus carolinensis (Bosc.) Fer. 



2. — Pallifera dorsalis (Binn.) Morse. 



3. — Agriolimax campestris (Say). 



4. — Pleurocera suhulare (Lea) Try. 



5. — Goniohasis livescens (Mke.) Try. The form with angular bodywhorl 



and more prominent suture, due to carina on whorls, also occurs. It is 

 known as G. cubicoides (Anth.) Try. 



6. — Vivipara 



With 4 distinct reddish-brown spiral bands; umbilicus partly 

 opened. V. contectoides Binn. 



Colored bands none, or obscure; umbilicus closed. 

 Diameter about equal height ; whorls all rounded. 



V. intertexta (Say) Binn. 

 Diameter less than height; bodywhorl often somewhat flattened 

 above. V. suhpurpurea (Say.) Binn. 



7. — Campeloma 



Ventricose, spire rather short. 



Eeddish within. C. rufum (Hald.) Call. 



Dark olive green, not reddish. C. ohesum Lewis 



Less ventricose; spire rather elongated. 

 Aperture 1/3 the length of the shell. 



C. subsolidum (Anth.) Call. 

 Aperture more than 1/3 the length of the shell. 



C. decisum (Say) Call. 



8. — Lioplax subcarinata (Say) Trosch. 



9. — Pyrgulopsis scalariformis (Wolf) Call & Pils. (Alluvial fossil.) 



10. — Pomatiopsis 



Shell brownish, 5 mm. long; terrestrial. P. lapidaria (Say) Try. 

 Shell greenish, 2-3 mm. long; aquatic. P. cincinnatiensis (Anth.) 



11. — Bythinella ohtusa (Lea) Binn. 



80 



